An assembled battery may be configured by electrically connecting a plurality of cells through a bus bar. For example, in Patent Document 1, a so-called cylinder-type battery is used as a cell, and a plurality of such cylinder-type batteries are electrically connected to each other by using a lead (bus bar). The lead is disposed at each end of the cylinder-type battery in a longitudinal direction.
In Patent Document 1, an exterior case for housing the plurality of cylinder-type batteries is provided with an air blow port and an air exhaust port. Air is taken in through the air blow port and is let out through the air exhaust port to cool the cylinder-type batteries housed in the exterior case.